WO2013160443A1

WO2013160443A1 - Intravascular rotary blood pump

Info

Publication number: WO2013160443A1
Application number: PCT/EP2013/058715
Authority: WO
Inventors: Thorsten Siess
Original assignee: Abiomed Europe Gmbh
Priority date: 2012-04-27
Filing date: 2013-04-26
Publication date: 2013-10-31
Also published as: KR20180132993A; EP2841124B1; USRE48649E1; DE102012207053A1; KR102121488B1; US9474840B2; KR101928544B1; US20150080743A1; KR20200067944A; JP2015514531A; AU2013254682A1; KR102033944B1; EP2841124A1; KR20150008133A; AU2013254682B2; KR102293322B1; JP6236433B2; KR20190119178A

Abstract

An intravascular rotary blood pump has a catheter (10), a pumping device (50), which is arranged distally from the catheter and has at its distal end a flexible flow cannula (53), through which blood is either sucked in or expelled by the pumping device (50) during the operation of the blood pump, and at least one pressure sensor (27, 28A, 30) having at least one optical fibre (28A), which is laid along the flow cannula (53). In this arrangement, the optical fibre (28A) and possibly a sliding tube (27), in which the optical fibre (28A) is laid, run(s) along a neutral axis of the flow cannula (53).

Description

The present invention relates to an intravascular rotary blood pump having one or more pressure sensors for measuring pressures within the patient's vascular system that are important to the operation of the blood pump and / or to assessing the health of the patient's heart.

In WO 2011/039091 AI, in connection with a cardiac assist system, a pressure measuring catheter is described, which has a catheter tube and a pressure sensor for measuring the pressure distally of the catheter tube. Specifically, the pressure measuring catheter has an optical pressure sensor and an elongated tube made of metal or of a high-strength plastic, for example PEEK, through which passes a loosely laid optical fiber of the optical pressure sensor. At the front (distal) end of the pressure measuring catheter is a sensor head, which works according to the Fabri-Perot principle. The sensor head has a cavity, which on the one hand is closed by a thin, pressure-sensitive glass membrane and on the other hand projects into the end of the optical fiber. The pressure-sensitive glass membrane deforms as a function of the size of the pressure acting on the sensor head. Reflection on the glass membrane causes the light emerging from the optical fiber to be modulated and fed back into the optical fiber. At the proximal end of the optical fiber there is an evaluation unit with integrated CCD camera, which evaluates the light obtained in the form of an interference pattern. In response, a pressure-dependent electrical signal is generated. Overall, it is thus an optoelectronic pressure sensor. The pressure measuring catheter is associated with intravascular

Cardiac assistive systems, such as an intra-arterial balloon pump (IABP) or intravascular rotary blood pump, are used by first advancing the subject cardiac assist system to the desired location of the patient's vascular system by means of a catheter tube, such as the aorta or ventricle. The pressure measuring catheter including the tube surrounding the optical fiber is displaceable relative to this catheter tube in its longitudinal direction and is subsequently inserted into the lumen of the catheter tube, advanced through the catheter tube and exits from the end thereof. When the sensor head has reached the intended measuring point, the tube of the pressure measuring catheter is withdrawn, but can also remain in place. In connection with a rotary blood pump, it is proposed to extend the pressure measuring catheter far beyond the distal end of the catheter tube and at the pump device

Rotate the rotary blood pump over so that it passes through the aortic valve and protrudes with its sensor head into the left ventricle, so as to measure the ventricular pressure. In principle, it would be desirable if the sensor head of the optical pressure sensor were already brought into place with the placement of the rotary blood pump, as is known, for example, in connection with pressure sensors in which the pressure is transmitted via a hydrostatic pressure transmission hose to an extracorporeal pressure measuring device. For example, from US 2003/0187322 AI a rotary blood pump is known, the pumping device has at the distal end of a flow cannula, in which a hydrostatic pressure transmission tube is embedded, which extends to the distal end of the flow cannula and is exposed to the local blood pressure. However, an optical pressure sensor comprising an optical fiber can not be easily routed along the flow cannula. Because the flow cannula is subjected to strong bends on their way to the placement in the heart, which would exercise not insignificant tensile and compressive stresses on a laid along the flow channels optical fiber. Even if the optical fiber were exposed within a separate pressure measuring lumen, the frictional forces due to relative movements between the optical fiber and the pressure gauge lumen could be so great that the optical fiber breaks. This applies in particular to glass optical fibers. Although these optical fibers are usually coated with a thin plastic coating, such as polyimide (Kapton), which represent a protection against breakage. Nevertheless, the risk of breakage is not excluded, and it would be very costly to have to replace the total placed in the patient blood pump, if the optical fiber actually breaks.

Object of the present invention is therefore to design a rotary blood pump with a fixed to the flow cannula sensor head of an optical pressure sensor such that the risk of breakage of the optical fiber light of the optical pressure sensor is largely reduced.

This object is achieved by an intravascular rotary blood pump with the features of claim 1. In dependent claims advantageous developments and refinements of the invention are ben ben specified.

Accordingly, in accordance with a preferred embodiment of the invention, an intravascular rotary blood pump comprises a catheter, a pump means located distally of the catheter, at its distal end a bend flexible flow cannula through which blood is either sucked or expelled from the pumping device during operation of the blood pump, and at least one pressure sensor with at least one optical fiber. According to the invention, the optical fiber is laid along a "neutral fiber" of the flow cannula.

The "neutral fiber" of the flow cannula extends in the longitudinal direction of the flow cannula and is characterized in that it is not or at least less, preferably significantly less bendable than the rest of the flow cannula, so that the flow cannula just not or at least not so easy along The neutral fiber bends when the blood pump with the flow cannula is preceded by the patient's vascular system, by definition, as the cannula bends, the neutral fiber lies exactly between the compressed and stretched areas and ideally does not undergo any change in length.

By virtue of the fact that the optical fiber runs along the neutral fiber of the flow cannula, ie coincides either with a neutral fiber or in the same "neutral bending plane" as the neutral fiber, the optical fiber experiences no compression or elongation when the rotary blood pump with the flow cannula ahead through the vascular System of the patient is guided and thereby adapts to the different radii of curvature of the vessels. In the simplest case, the optical fiber inside or outside at the

Flow cannula along a neutral fiber of the flow cannula are glued by means of an elastic adhesive. To be on the safe side, however, it is preferable for the optical fiber to be freely movable within a sliding tube laid along the neutral fiber, so that the optical fiber can be additionally inserted. To protect against breakage due to stretching or compression.

The neutral fiber of the flow cannula can be realized in various ways. So it is possible, for example, by local reinforcement of

Flow cannula, such as by introducing or applying a rigid or tension-pressure-stiff strip along the flow cannula, impart a neutral fiber so to speak. This is particularly suitable for rotary blood pumps whose flow cannula extends in a straight line in the normal state. This local reinforcement can be achieved for example by a sufficiently rigid lumen or sliding tube in which the optical fiber is laid.

Frequently, however, the flow cannula is given a pre-curvature. When navigating the rotary blood pump through the vascular system of the patient, the flow cannula then bends so that this predetermined curvature increases and decreases depending on the bending direction. Accordingly, there is a neutral fiber between the inner radius of curvature defined by the pre-curvature and the outer radius of curvature of the flow cannula, that is to say a total of two neutral fibers, namely on both sides of the flow cannula. The pre-curvature can in turn be predetermined or stabilized by means of a rigid strip along the neutral fiber or fibers. In the event that despite the laying of the optical fiber along the neutral fiber of the flow cannula there is a risk of stretching or compression of the optical fiber, it is - as stated - preferred to move the optical fiber freely movable in a separate sliding tube. Nevertheless, in this case too, as already stated, fiber breaks can occur come about because the fiber inside the sliding tube is subject to excessive stretching or compression due to high friction. Preferably, a sliding material pairing with a low coefficient of friction is therefore selected for the outer surface of the optical fiber and the inner surface of the sliding tube. This may be a metal-metal Gleitmaterialpaarung, a metal-plastic Gleitmaterialpaarung or a plastic-plastic material pairing, wherein the plastic is preferably polytetrafluoroethylene (PTFE) or at least. For this purpose, the optical fiber is coated on the outside accordingly with polytetrafluoroethylene. By contrast, conventional optical fibers are usually coated with polyimide (Kapton). However, the optical fiber may also have an outer metal coating, which may, for example, be vapor-deposited to form a metal-metal sliding material pairing or metal-plastic sliding material pairing with the inner surface of the sliding tube. Because metal regularly has a lower coefficient of friction than the usual plastics.

The sliding tube, in which the optical fiber is laid freely movable, may be a simple tube, in particular a flexible tube, which is possible due to the fact of its laying along the neutral fiber of the flow cannula. However, preference is given to a metallic material for the sliding tube, which is optionally plastic-coated on the inside, preferably again with polytetrafluoroethylene (PTFE). A metallic sliding tube is resistant to pressure and tension and is therefore suitable for imparting a neutral fiber to the flow cannula. In such rotary blood pumps whose flow cannula is already predetermined by Vorkrümmung a neutral fiber, this neutral fiber is additionally stabilized by the metallic sliding tube. It is particularly preferred if the sliding tube is formed from a material comprising a shape memory alloy. The most well-known representative of such a shape memory alloy is the so-called "nitinol." The particular advantage of shape memory alloys in the present context is that shape memory alloys exhibit superelastic behavior, which means that the flow cannula can also follow extreme curvatures without plastically deforming the sliding tube Rather, the sliding tube bends back to its original shape, because of this special material property, the lumen can be made very small with little play for the optical fiber A further advantage of a shape memory metal sliding tube is the drastically reduced resistance to breakage in the event of multiple bending or buckling loads, whereas a "normal" metal tube in this case breaks more easily and d represents a local vulnerability, thus the probability of subsequent fiber breakage even increased, the tube of shape memory metal remains flexible elastic longer and thus further reliably prevents fiber breakage.

It is further preferred if the sliding tube, in which the optical fiber is moved freely movable, is filled with liquid. As a result, the frictional forces between the surface of the optical fiber and the surface of the sliding tube can be further reduced.

As the optical fiber, a glass fiber is preferably used because they are easy to handle and inexpensive. In particular, there are very thin Glass fibers which, due to their small diameter, do not break even with very tight bending radii. This is in connection with the attachment of the optical fiber on the flow cannula of particular importance, because it may happen that the flow cannula when advancing through the blood vessels runs on an obstacle, such as the sinus of the aortic valve, and folds for a short time by 180 °.

In addition, a small diameter of the optical fiber is also advantageous in order to minimize the cross-sectional dimensions of the blood pump. This applies in particular if the optical fiber or the sliding tube containing the optical fiber extends outside along the flow cannula. Because the larger the diameter of the optical fiber or the diameter of the sliding tube, the larger the cross-sectional dimensions of the blood pump, and this can be at a disadvantage when placing the blood pump and / or operation of the blood pump in the patient's vascular system. It is therefore preferred to provide an optical fiber, in particular an optical fiber comprising a glass fiber, with a diameter of 130 μm or less. As far as the sensor head of the pressure sensor or, in general terms, the distal end of the pressure sensor is fixed to the outside of the flow cannula, so approximately at a lying at the distal end of the flow cannula intake basket, the sensor head is at least partially received in a recess in the outer surface of the Flow cannula is provided. This protects the sensitive sensor head from collision with a sluice valve or hemostasis valve when the blood pump is inserted into the patient's vasculature. However, it may be the case that the wall thickness of the flow cannula is insufficient to produce a depression having a depth in which the sensor head can be completely received so that the distal end of the pressure sensor projects radially beyond the periphery of the flow cannula. In particular for these cases, it is advantageous to provide a bead, which also projects beyond the periphery of the flow cannula, distally in front of the sensor head so that the hemostasis valve or lock valve does not catch on the distal end of the pressure sensor when the blood pump is inserted into the patient's vascular system. Alternatively, this bead can also be designed so that it is present not only distally in front of the sensor but also laterally or also proximally. Advantageously, this U- or O-shaped bead is designed so that the sensor head contour completely immersed in the protective contour, so no on the protective contour (bead) protruding edges. This bead may be, for example, an adhesive bead, which may also be applied after fixing the sensor head in the recess. The bead may alternatively be welded or soldered to the flow cannula.

The invention will be explained below by way of example with reference to the accompanying drawings. Show:

FIG. 1 shows a blood pump displaced through the aorta, which extends through the aortic valve into the left ventricle, with integrated pressure sensor, FIG. 2 shows an optical pressure sensor with optical fiber,

FIG. 3 shows the pump device of the blood pump from FIG. 1 in greater detail,

4 A, 4B, the detail A of Figure 3 in plan view and in side view, Figures 5 A, 5B the detail B of Figure 3 in plan view and in side view and

6 shows a cross section through a pressure sensor with guided in a sliding tube optical fiber.

FIG. 1 shows an intravascular blood pump with a catheter 10 which has been inserted retrograde into the descending aorta 11. The descending aorta is part of the aorta 12, which initially rises from the heart and then leads downward and has the aortic arch 14. At the beginning of the aorta 12 is the aortic valve 15 which connects the left ventricle 16 to the aorta 12 and through which the intravascular blood pump extends. The intravascular blood pump comprises, in addition to the catheter 10, a rotary pump device 50 attached to the distal end of the catheter tube 20, comprising a motor part 51 and an axially spaced pump part 52 and a flow cannula 53 distally projecting from the suction end of the pump part 52 has, at the end of which a suction inlet 54 is located. Provided distally of the suction inlet 54 is a soft-flexible tip 55, which may, for example, be in the form of a "pigtail" or in the shape of a J. Through the catheter tube 20 run various conduits and devices which are important for the operation of the pumping device 50 1 only two optical fibers 28A, 28B are shown, which are connected at their proximal end to an evaluation device 100. These optical fibers 28A, 28B are each part of an optical pressure sensor whose sensor heads 30 and 60 on the one hand on the outside of the housing Pump part 52 and on the other hand outside near the suction inlet 54. The transmitted from the sensor heads 30 and 60 pressure is converted in the evaluation device 100 into electrical signals and displayed, for example, on a display 101. By measuring both the aortic pressure by means of the sensor head 60 and the ventricular pressure by means of the sensor head 30, in addition to the actual pressure signal, a contractility measurement, in which the recovery of the heart is measured, as well as the determination of the pressure difference, which is used to calculate the flow of the pump device 50 is included, possible.

The principle of the electro-optical pressure measurement is explained in more detail below with reference to FIG. Figure 2 shows a pressure measuring catheter 26 with a lumen or sliding tube 27 in which an optical fiber 28 A (it could also be multiple optical fibers or the optical fiber 28 B) is freely movable. The sliding tube 27 may consist of a polymer, in particular polyurethane, or preferably of nitinol or of another shape memory alloy, emerge from the catheter tube 20 at an exit point 57 (see FIG. 1) and be routed along the flexible flow cannula 53, for example outside. Within the catheter tube 20 can be dispensed with the separate sliding tube 27. At the distal end 34 of the optical fiber 28 A, the pressure measuring catheter has a sensor head 30 with a head housing 31, which contains a thin glass membrane 32, which closes off a cavity 33. The glass membrane 32 is sensitive to pressure and deforms as a function of the size of a pressure acting on the sensor head 30. By the reflection on the membrane, the light emerging from the optical fiber 28 A light is reflected modulating and coupled back into the optical fiber. The coupling can take place either directly in the mold 28A or indirectly via a cavity 33 which closes the cavity in a vacuum-tight manner. Advantageously, the floor 37 is an integral part of the head housing 31. Thus, the determination of the pressure in the cavity 33 can be independent of the mounting of the optical fiber 28 A done. At the proximal end of the optical fiber 28 A, ie in the evaluation device 100, there is a digital camera, such as a CCD camera or a CMOS, which evaluates the incoming light in the form of an interference pattern. Depending on this, a pressure-dependent electrical signal is generated. The evaluation of the optical image or optical pattern supplied by the camera and the calculation of the pressure are carried out by the evaluation unit 100. This gives the already linearized pressure values to the controller, which also the power supply to the motor-driven pumping device 50 in dependence completed evaluation of the pressure signal controls. Instead of the optical pressure sensor described in relation to FIG. 2, which operates according to the Fabri-Perot principle, other optical pressure sensors with one or more optical fibers can also be used.

The pump device 50 from FIG. 1 is shown in more detail in FIG. One can see a drive shaft 57 projecting from the motor part 51 into the pump part 52, which drives an impeller 58, by means of which blood is sucked through the blood passage openings 54 at the distal end of the flexible flow cannula 53 during operation of the blood pump and proximally from the impeller 58 through the blood flow passage openings 56 is ejected. The pumping device 50 can also promote in the reverse direction, if it is adjusted accordingly. Through the catheter tube 20 of the catheter 10 through to the pumping device 50 on the one hand lead the already mentioned optical fibers 28A, 28B and a power supply line 59 A for the motor part 51 and a rinsing liquid line 59B.

The sensor head 60 of the first pressure sensor is fixed on the outside of the pump housing of the pump part 52. The associated optical fiber 28B is guided within the catheter tube 20 over a short distance of, for example, 5 cm in a thin plastic tube 21 to strong curvatures of the catheter 10 in this region of the catheter tube 20 to ensure that the optical fiber 28B does not break. Outside the pumping device 50, the optical fiber 28B is laid freely and glued only by means of adhesive to the outer wall of the pumping device 50. As a result, the outer cross-sectional dimensions of the pumping device 50 are kept to a minimum. The bonding of the optical fiber 28B is possible because the pumping device 50 is rigid in this area and therefore the optical fiber 28B need not be able to move relative to the pumping device 50. In contrast, leading to the sensor head 30 of the second pressure sensor optical fiber 28 A along the entire periphery of the pumping device 50 in a tube or tube, preferably a nitinol tube, freely laid so that they within this tube or tube in bending changes of the flow cannula 53rd can shift relative to the pumping device 50. The tube thus forms the sliding tube 27 for the optical fiber 28A and extends along a neutral fiber of the flow cannula 53 on the outer surface of the flow cannula. It is likewise possible to lay the sliding tube 27 in the interior of the flow cannula 53, in particular if a pressure in the interior of the flow channel 53 is to be measured, or to integrate it into the wall of the flow cannula 53.

The neutral fiber of the flow cannula 53 results in the exemplary embodiment illustrated in FIG. 3 in that the flow cannula has a pre-curvature which facilitates the laying of the blood pump in the vascular system of the patient. As a result of this pre-curvature, the flow cannula 53 has an inner radius of curvature and an outer radius of curvature, between which a neutral bending plane extends approximately in the center. Where this central bending plane intersects the flow cannula 53 has the flow cannula neutral fibers. The predetermined by the Vorkrümmung neutral fiber or neutral plane of the flow cannula 53 is reinforced by the sliding tube 27 laid there. However, as the neutral fiber of the flow cannula in the sense of the present invention, all other lines running within the neutral plane are also to be understood, since no line or "fiber" extending within this plane is subjected to compressive or tensile stresses when the pre-curvature of the flow cannula 53 The reinforcement of the neutral fiber by the sliding tube 27 can also be of particular advantage since this prevents or at least reduces the bending of the cannula perpendicular to the plane of the leaf.This anisotropy can be achieved by the user As explained in the beginning, the optical fiber 28A can also be laid and fixed directly along a neutral fiber of the flow cannula 53 without an additional sliding tube 27. The free laying of the optical fiber 28A within the space along the neutral The fiber-laid sliding tube 27 serves only for additional security against breakage of the optical fiber 28A.

The tube and / or the tube of the sliding tube 27, in which the optical fibers 28A, 28B are laid, may extend into the catheter tube 20 for a short time, but may also extend completely through the catheter tube 20 and into a corresponding plug at the end the line for insertion of the respective pressure sensor in a terminal of the evaluation 100 end.

Distal before and / or next to and / or behind the sensor heads 30 and 60, a bead 35 or 65 is respectively provided, which the sensor heads 30 and 60 Protect from damage by inserting the blood pump through a hemostasis valve or lock valve. In addition, the sensor heads 30 and 60 are each embedded in a recess 36 or 66 of the pump device 50. The latter is not shown in FIG. 3 and will be explained below with reference to FIGS. 4A, 4B and 5 A, 5B.

Figure 4A shows the detail A of Figure 3 in greater detail and partially in cross section. Figure 4B shows basically the same section A but in top view. Accordingly, the sensor head 60 is received sunk in a recess 66 provided on the outer surface of the pump part 52, the depression 66 being surrounded by a horseshoe or U-shaped bead 65. The bead could also be closed to an O-shape. It is glued or welded, but can also form an integral part of the pump part 52. The optical fiber 28B is adhered to the surface and extends along a land between two blood flow passages 56.

Similarly (FIGS. 5A and 5B), the sensor head 30 of the second pressure sensor is also recessed in a recess 36 on the outer surface at the distal end of the flow cannula 53. Here, too, the nitinol tube 27 extends with the optical fiber 28 A laid therein through a web between two blood flow passages 54. A point-shaped bead 35 distally immediately in front of the recess 36 protects the sensor head 30 from collision damage when the blood pump is inserted. The bead 35 may alternatively Uf örmig or Of örmig formed and in particular glued, welded or an integral part of the flow cannula 53. The sensor head 30 may alternatively extend together with the sliding tube 27 up to an arbitrary point of the soft-flexible tip 55 and be mechanically protected there, for example by the lining of the soft-flexible tip 55. Bend-induced pressure artifacts are low because the sensor membrane is orthogonal to the wall. Only the adhesive connection between the optical waveguide 34 and the sensor head must be protected against bending. This can be done through the tube 27 or additional stiffening in the region of the bond. The optical fiber 28B as well as the optical fiber 28A are preferably glass fibers, which are usually polymer coated. However, optical fibers made of plastic can also be used. However, glass optical fibers can be made particularly thin, which - especially in combination with the additional sliding tube 27 - is favorable in order to keep the overall cross section of the pumping device 50 low. In this respect, it is advantageous to use optical fibers with a glass core, which do not exceed a total diameter of 130 μπ. Although such thin optical fibers are particularly vulnerable to breakage when subjected to tensile or compressive forces. The arrangement of the optical fiber along the neutral fiber of the flow cannula 53, however, largely reduces this risk. The sliding tube 27 may then have an inner diameter of only 150 μm. The outer diameter is then slightly above it, for example at 220 μιη, so that the total cross section of the pumping device 50 is not significantly increased. For it has to be taken into account that the sliding tube 27 is always outside the at least in the region of the pump part 52

Pumping device 50 must be laid. Tubes of the shape memory alloy Nitinol are commercially available with the aforementioned inside and outside diameters. However, it is also possible to use sliding tubes, in particular nitinol tubes, with larger diameters. For example, an inner diameter of 230 microns and an outer diameter of 330 μηι. The optical fiber 28A may then also have a correspondingly larger diameter. FIG. 6 shows a cross section through a sliding tube 27 with an optical fiber 28 laid therein, which has a glass fiber core 28 _CO re, a so-called glass cladding 28 _c iad and an outer polymer coating

28 _C oat includes. The different refractive indices of the optical fiber core 28 _C ore and of the optical fiber cladding 28 _c iad ensure that light coupled into the optical fiber core is guided along the optical fiber 28 with virtually no loss. The outer coating 28 _CO at serves to protect the optical fiber 28 against breakage. While the coating 28 _{CO is} usually a polyimide coating, it is advantageous in the context of the present invention to provide a coating 28 _CO at as low a friction as possible, in particular of polytetrafluoroethylene (PTFE). The outer coating 28 _CO at may also be a metallic coating. The glass fiber core 28 _CO re may have a diameter of, for example 62.5 μηι. The reflection layer could then increase the diameter to 80 μm. The coating 28 _CO at may have a thickness of 10 μπι. The diameter of the optical fiber 28 is preferably about 100 μπι or less in total.

A distinction is made between normal optical fibers and gradient index fibers. For gradient index fibers, the glass fiber cladding 28 _c iad is formed by many superimposed glass layers with different refractive indices. The use of gradient index fibers is preferred in the context of the present invention because they are more bendable and lossless than simple glass fibers. The sliding tube 27 in turn consists of an outer jacket 27a, with an inside coating 27i. The outer jacket 27a substantially defines the flexure and extension characteristics of the slider tube 27, while the inboard coating 27i is essential for reducing the frictional forces acting between the slider tube 27 and the optical fiber 28. The inner coating 27i is therefore preferably a metallic coating or again a low-friction polymer coating, in particular of polytetrafluoroethylene. The sliding tube 27 may additionally be filled with a liquid in order to keep low frictional forces occurring.

Claims

1. Intravascular rotary blood pump comprising a catheter (10), a pumping device (50) disposed distally of the catheter (10) and having at its distal end a flexurally flexible flow cannula (53) through which the blood pump operates Blood is sucked or expelled from the pump means (50), and at least one pressure sensor (27, 28A, 30) is provided with at least one optical fiber (28A), characterized in that the optical fiber (28A) is along a neutral fiber of the flow cannula (53). is relocated.

2. A blood pump according to claim 1, wherein the neutral fiber is predetermined by a pre-curvature of the flow cannula (53) and accordingly lies between an inner curvature radius defined by the pre-curvature and the outer curvature radius of the flow cannula.

3. A blood pump according to claim 1 or 2, wherein the optical fiber (28 A) is glued along the neutral fiber.

4. A blood pump according to claim 1 or 2, wherein the optical fiber (28A) along the neutral fiber in a sliding tube (27) is moved freely movable.

The blood pump of claim 4, wherein the sliding tube (27) extends outwardly along the flow cannula (53).

A blood pump according to claim 4 or 5, wherein an outer surface of the optical fiber (28A) and an inner surface of the sliding tube (27) have a Pair of sliding material of metal-metal, metal-plastic or plastic plastic form, wherein the plastic preferably comprises polytetrafluoroethylene (PTFE).

7. A blood pump according to any one of claims 4 to 6, wherein the sliding tube (27) is formed of a material comprising a shape memory alloy.

8. A blood pump according to any one of claims 4 to 7, wherein the sliding tube (27) is plastic coated on the inside.

A blood pump according to any of claims 4 to 8, wherein the optical fiber (28A) has an outer metal coating (28 _CO at).

A blood pump according to any one of claims 4 to 8, wherein the optical fiber (28A) has an outer plastic coating (28 _COat ) of polytetrafluoroethylene

(PTFE).

11. A blood pump according to any one of claims 4 to 10, wherein the sliding tube (27) is filled with liquid.

The blood pump of any one of claims 1 to 11, wherein the optical fiber (28A) comprises a glass fiber (28 _CO re, 28 _c iad, 28 _CO at).

13. Blood pump according to one of claims 1 to 12, wherein the optical fiber (28 A) has a diameter of 130 μπι or less.

14. A blood pump according to any one of claims 1 to 13, wherein the flow cannula (53) has an outer surface in which a depression (36) is provided. is formed, in which a distal end (30) of the pressure sensor is at least partially disposed.

15. A blood pump according to any one of claims 1 to 14, wherein the flexurally flexible flow cannula (53) has a soft flexible tip (55) and wherein a distal end (30) of the pressure sensor is at least partially disposed in the soft flexible tip (55).

16. A blood pump according to any one of claims 1 to 15, wherein a distal end (30) of the pressure sensor extends radially beyond the periphery of the flow cannula (53), and at the flow cannula (53) distal to the distal end (30) of the pressure sensor also on the periphery of the flow cannula (53) protruding bead (35) is provided.